Thursday 25 May 2023


From 9:00 am-9:45 pm CEST

7.00 am UTC

(check your timezone

Retrieval of Sea Surface Temperature from HY-1C COCTS

The Haiyang-1C (HY-1C) satellite is the first operational ocean colour satellite of the Chinese HY-1 series satellites, launched in September 2018. The Chinese Ocean Color and Temperature Scanner (COCTS) on board the HY-1C satellite has two thermal infrared channels with a spectrum range of 10.30-11.40 μm and 11.40-12.50 μm for sea surface temperature (SST) observations. Two infrared channels of COCTS were intercalibrated with the Infrared Atmospheric Sounding Interferometer (IASI) onboard the MetOp-B satellite. After inter-calibration, the calibration of the HY-1C COCTS thermal infrared channels remains stable and the accuracy is around 0.2 K. Furthermore, the Bayesian cloud detection and optimal estimation (OE) SST retrieval were applied to COCTS data in this study. The Bayesian cloud detection algorithm that has been developed is based on Bayes’ theorem and used simulation of COCTS observations. The MODerate resolution atmospheric TRANsmission (MODTRAN) model was used for the simulation of COCTS brightness temperatures. Global SSTs were retrieved from COCTS by OE from July 2019 to August 2019. The quality indication was conducted mainly based on the clear-sky probability and the value of each pixel. The COCTS retrieved SST were validated using iQuam buoy SST and Sea and Land Surface Temperature Radiometer (SLSTR) SST. Comparison of COCTS OE SST with in situ SST showed that the COCTS SSTs are cooler than in situ measurements by −0.16 ºC on average, and the standard deviation (SD) of differences was 0.46 ºC. The mean difference of COCTS OE SST with matched skin temperatures from the SLSTR is -0.02 ºC, with an SD of 0.45 ºC. These validation results of COCTS OE SST demonstrated that Bayesian cloud detection and OE SST retrieval algorithm worked well for HY-1C COCTS.

Speaker’s profile

Dr Liu received a PhD degree in Marine Detection Technology from the Ocean University of China (2019). Dr Liu’s research interests include the inter-calibration of thermal infrared and microwave sensors, sea surface temperature retrieval and validation. Dr Liu is a member of the GHRSST international science team.



Recording of the talk is now available on YouTube: